Internal combustion engines such as used in the modern automobile have provisions for using the vacuum pressures present in the in-take manifold to operate vacuum motors, sensors, and such, and diagnoses purposes of engine performance. The vacuum motors, sensors and such normally connect to the pressures within the in-take manifold by means of flexible resilient tubing. The construction of the vacuum system heretofore are not provided with means to easily connect service equipment such as a pressure indicating devices, in convenient locations of the vacuum system to measure the amount of pressure within the in-take manifold and vacuum system.